Luca Frassinella, Ecosmic; Benedetta Margrethe Cattani, Ecosmic; Jorge Martinez Castillo, Ecosmic; Antonio D’Anniballe, Cranfield University; Leonard Felicetti, Cranfield University
https://doi.org/10.64861/OCMI4276
Keywords: space-based, non-earth imaging, network, star trackers, sensors
Abstract:
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The growing need for scalable, resilient and cost-effective Space Domain Awareness (SDA) capabilities motivates the exploration of architectures that do not rely exclusively on dedicated surveillance constellations. While vertically integrated systems promise performance optimization, they require significant capital expenditure and long deployment timelines. This work investigates an alternative approach: achieving meaningful surveillance coverage by leveraging optical sensors that are already operational in space, repurposed opportunistically for space surveillance activities. The resulting architecture is assessed as a distributed, federated alternative to vertically integrated initiatives such as SpaceX’s Stargaze concept._x000D_
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The study is conducted from the perspective of an independent SDA service provider that neither owns nor operates satellites, but instead acts as a super partes data aggregator and network orchestrator. In this role, the provider coordinates heterogeneous space-based sensors contributed by third-party operators and integrates their observations into a unified surveillance capability. The central research question is whether a heterogeneous federated network can provide surveillance performance comparable to representative large single-operator observation constellations. The analysis explicitly accounts for sensor field-of-view constraints, pointing limitations, orbital geometry, line-of-sight visibility and illumination conditions._x000D_
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Four representative observation architectures are simulated and compared. Two correspond to a federated network equipped with either wide- or narrow-field-of-view optical payloads, based on the anonymized, real-world orbital distribution of satellites provided by participating commercial operators. The other two architectures serve as benchmarks and are representative of large single-operator constellations inspired by OneWeb- and Starlink-like deployments, equipped with star trackers. All considered architectures are simulated under a common observation model and the same visibility constraints, to enable a consistent comparison of their surveillance capabilities._x000D_
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Performance is evaluated through two main and complementary metric families: coverage and timeliness. Coverage is quantified in terms of the number of resident space objects that can be observed as a function of altitude and inclination ranges, while also assessing the sensitivity to the minimum detectable object size. Detection capability is modelled by combining sensor aperture characteristics, signal-to-noise considerations and phase angle constraints to determine object size thresholds within defined orbital shells. In addition to the number of observed targets, coverage performance is also assessed through cumulative time under tracking of the targets and observation quality, measured by the observer-target distance during tracking. This metric provides insight into the proximity at which the different architectures can observe the population of resident space objects. Sensitivity analyses examine how coverage of the federated network varies with modeled target size, sensor heterogeneity and camera pointing direction._x000D_
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Timeliness metrics capture the responsiveness of the distributed network and are evaluated through two complementary metrics: observation latency, which is defined as the time elapsed from the beginning of the simulation to the first observation of a target, and revisit time, defined as the minimum time between two subsequent observations of the same object. The expected revisit time is evaluated under collective tasking scenarios, accounting for overlapping visibility opportunities and illumination-driven availability windows. The analysis also relates the cumulative time under tracking as a function of the orbital distribution of the observation networks, highlighting the influence of altitude and inclination on the observable target population._x000D_
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Results provide quantitative insight into the trade space between network composition, achievable detection thresholds, and temporal responsiveness. The findings support an assessment of whether a federated optical sensing architecture, coordinated by an independent SDA provider, can deliver operationally meaningful surveillance performance while maintaining economic sustainability. By coupling realistic performance modelling with considerations of data-sharing feasibility, the study contributes to both technical and systemic understanding of distributed space-based optical surveillance as a viable complement, or alternative, to dedicated SDA constellations._x000D_
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Date of Conference: September 15-18, 2026
Track: Space-Based Assets